This invention relates to an X-ray, neutron or electron diffraction method and an apparatus therefor for analyzing a sample, such as various materials and devices, in non-destructive mode and without contact.
As an apparatus for analyzing a sample, such as various materials and devices, in non-destructive mode and without contact, there has been hitherto widely used an apparatus utilizing X-ray diffraction. As a detector for such an apparatus, a solid state detector, a scintillation counter, a proportional counter or a film has been conventionally used. Recently, an imaging plate (photoluminescent sheet), a position sensitive proportional counter detector, an arrayed solid state detector and a position sensitive proportional detector have been developed.
Of these various detectors, the imaging plate has merits that it is a two-dimensional detector, it has a high sensitivity and a wide dynamic range and it provides highly fine and precise detection. The imaging plate has an additional merit that the data processing is easy, because the imaging plate permits image data to be converted into two-dimensional digital data by analogue/digital conversion.
The imaging plate, however, does not have energy resolution. Namely, when an X-ray diffraction image is formed using the imaging plate, the image data of respective pixels are those measured as a set of various photons occurring during the scanning through a full scanning angle of a sample. As a result, depending upon the elements contained in the sample, noises resulting from fluorescence, scattered X-rays from air or apparatus parts and inelastic scattering cannot be separated from X-ray diffraction, so that the S/N ratio is extremely low and the detection performance is very low. For example, in analyzing a sample such as a superconductor film grown on a substrate, not only the required information of the film but also information, including fluorescence and diffraction, from the substrate are detected together, so that the detection performance is unsatisfactory.